A novel nonlinear model for surface permanent magnet synchronous motors（SPMSMs） is adopted to estimate the initial rotor position for hybrid electric vehicles（HEVs）. Usually, the accuracy of initial rotor position...A novel nonlinear model for surface permanent magnet synchronous motors（SPMSMs） is adopted to estimate the initial rotor position for hybrid electric vehicles（HEVs）. Usually, the accuracy of initial rotor position estimation for SPMSMs relies on magnetic saturation. To verify the saturation effect, the transient finite element analysis（FEA） model is presented first. Hybrid injection of a static voltage vector（SVV） superimposed with a high-frequency rotating voltage is proposed. The magnetic polarity is roughly identified with the aid of the saturation evaluation function, based on which an estimation of the position is performed. During this procedure, a special demodulation is suggested to extract signals of iron core saturation and rotor position. A Simulink/MATLAB platform for SPMSMs at standstill is constituted, and the effectiveness of the proposed strategy is verified. The proposed method is also validated by experimental results of an SPMSM drive.展开更多
本文旨在利用流体体积(Volume of Fluid,VOF)方法捕捉和界面重构,对单个三维气泡在搅拌槽中的运动进行了数值模拟,研究两相相互作用过程中气泡在搅拌槽中的运动及变形。在考虑表面张力和重力的情况下,实时计算了质量和动量守恒方程。压...本文旨在利用流体体积(Volume of Fluid,VOF)方法捕捉和界面重构,对单个三维气泡在搅拌槽中的运动进行了数值模拟,研究两相相互作用过程中气泡在搅拌槽中的运动及变形。在考虑表面张力和重力的情况下,实时计算了质量和动量守恒方程。压力-速度耦合通过SIMPLE方案实现,界面重构采用几何重构PLIC方案。本文分析了在搅拌槽中搅拌速度、气泡尺寸、表面张力、密度比、气泡初始位置对气泡运动与变形的影响。结果表明,搅拌产生的液体流动能够改变气泡的形状,而增加搅拌速度则能加速气泡的运动和变形过程;表面张力能够维持气泡的形状,阻止其发生变形;气泡初始尺寸与密度比影响气泡的速度,初始尺寸与密度比越大,速度越大,变形越明显;气泡的初始位置对气泡的运动轨迹和变形有影响,距离搅拌轴越近,所受液体流动的作用力逐渐增大,导致气泡的变形更加显著,到达搅拌区域的时刻更早。本文研究结果可对优化浮选工艺参数,提高矿物浮选效率提供理论参考依据。展开更多
基金Project supported by the National Natural Science Foundation of China（Nos.51207029 and 51507039） the Fundamental Research Funds for the Central Universities,China（No.HIT.NSRIF.2017013） the China Postdoctoral Science Foundation（No.2016M591529）
文摘A novel nonlinear model for surface permanent magnet synchronous motors（SPMSMs） is adopted to estimate the initial rotor position for hybrid electric vehicles（HEVs）. Usually, the accuracy of initial rotor position estimation for SPMSMs relies on magnetic saturation. To verify the saturation effect, the transient finite element analysis（FEA） model is presented first. Hybrid injection of a static voltage vector（SVV） superimposed with a high-frequency rotating voltage is proposed. The magnetic polarity is roughly identified with the aid of the saturation evaluation function, based on which an estimation of the position is performed. During this procedure, a special demodulation is suggested to extract signals of iron core saturation and rotor position. A Simulink/MATLAB platform for SPMSMs at standstill is constituted, and the effectiveness of the proposed strategy is verified. The proposed method is also validated by experimental results of an SPMSM drive.
文摘本文旨在利用流体体积(Volume of Fluid,VOF)方法捕捉和界面重构,对单个三维气泡在搅拌槽中的运动进行了数值模拟,研究两相相互作用过程中气泡在搅拌槽中的运动及变形。在考虑表面张力和重力的情况下,实时计算了质量和动量守恒方程。压力-速度耦合通过SIMPLE方案实现,界面重构采用几何重构PLIC方案。本文分析了在搅拌槽中搅拌速度、气泡尺寸、表面张力、密度比、气泡初始位置对气泡运动与变形的影响。结果表明,搅拌产生的液体流动能够改变气泡的形状,而增加搅拌速度则能加速气泡的运动和变形过程;表面张力能够维持气泡的形状,阻止其发生变形;气泡初始尺寸与密度比影响气泡的速度,初始尺寸与密度比越大,速度越大,变形越明显;气泡的初始位置对气泡的运动轨迹和变形有影响,距离搅拌轴越近,所受液体流动的作用力逐渐增大,导致气泡的变形更加显著,到达搅拌区域的时刻更早。本文研究结果可对优化浮选工艺参数,提高矿物浮选效率提供理论参考依据。
